The Seacoast Region is the southeast area of the U.S. state of New Hampshire that is centered around the city of Portsmouth. It includes the eastern portion of Rockingham County and the southern portion of Strafford County. At its narrowest definition, the region stretches 13 miles (21 km) along the Atlantic Ocean from New Hampshire's border with Salisbury, Massachusetts, to the Piscataqua River and New Hampshire's border with Kittery, Maine. The shoreline alternates between rocky and rough headlands and areas with sandy beaches. Some of the beaches are bordered by jetties or groins, particularly in the towns of Rye and Hampton. Most definitions of the Seacoast Region includes some inland towns as well, including the Great Bay area cities of Dover and Rochester, the college town of Durham, and areas as far west as Epping. Some definitions also include nearby portions of York County, Maine that are culturally aligned with the Portsmouth area rather than the Portland, Maine metropolitan area.

New Hampshire is a state in the New England region of the Northeastern United States. It borders Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec to the north. Of the 50 U.S. states, New Hampshire is the fifth smallest by area and the tenth least populous, with a population of 1,377,529 residents as of the 2020 census. Concord is the state capital and Manchester is the most populous city. New Hampshire's motto, "Live Free or Die", reflects its role in the American Revolutionary War; its nickname, "The Granite State", refers to its extensive granite formations and quarries. It is well known nationwide for holding the first primary in the U.S. presidential election cycle, and for its resulting influence on American electoral politics.